Manufacture of block grease



Patented Mar. 4, 1952 MANUFACTURE BLOCK GREASE Albert E. Ogden,Franklin, Pa., Richard A. Butcosk, Jackson Heights, N. Y., and RaymondC. Williams, Franklin, Pa., assignors to Socony- Vacuum Oil Company,IneorporatedNew York, N. Y., a corporation of New York No Drawing.Application July 28, 1949, SerialNo. 107,378

4 Claims.

This invention relates to the manufacture of block greases and isconcerned with addition of a small amount of a surface active materialto the grease batch which results in great reductions in the lossesnormally incident to the manufacture of block greases due to rejectionof portions of the batch.

The block greases are a group of hard greases having high penetrationvalues used in the form of firm blocks for lubrication of hightemperature bearings such as those on rotary kilns used in cementmanufacture, paper mill dryer rolls, textile calender rolls and thelike. The structure of these greases has a very significant bearing onthe rate of consumption in use and good block greases are characterizedby the presence of small pockets of oil in the grease and freedom frominclusion of pockets of air or other gas.

The block greases are typically high soap content anhydrous greasescontaining about 20 per cent or more of soap and as small a watercontent as can be obtained without overcooking, say less than about 1per cent. These greases are prepared by cooking together suitableingredients and raising the temperature of the batch suificiently highto dehydrate and then pouring the grease into pans about 6 inches deepand allowing the grease to cool in the pans. In a typical operation thepans are about 4 inches wide, 6 inches deep and 46 inches long.

Conventional block greases have the manufacturing disadvantage oftending to bread loaf in the cooling pans. The term applied to thisdisadvantage is peculiarly descriptive in that the grease in. thecooling pan will acquire a hard upper crust due to cooling and the crustwill then rise up and crack in a manner strongly reminiscent of oldfashioned home baked bread. That portion of the block lying under theraised and broken crust is found to be highly porous and this porositymay extend to a considerable depth of the grease in the pan. Grease ofthis nature is unsuitable for the desired use and must be cut off andrejected. In extreme cases the rate of rejection due to bread loafingand related phenomena may run as high as 60 per cent of the batch.

Although the rejected grease can be added to a subsequent batch andreworked, rejection represents a serious economic loss because of thehigh cost for labor and utilities involved in breaking up the rejectedgrease, supplying it to the kettle, heating it and maintaining it atcooking temperature for the required period of time and again pouring itinto pans by the use of hand ladles.

A'further source of loss in this type of operation is that the capacityof the expensive kettles representing substantial capital investment isgreatly reduced.

It has been found that a number of materials tend to reduce breadloafing but all of them known prior to this invention also have theefiect of altering the structure of the. grease: in such manner that ithad to be rejected as unsuitable. For example, glycerol may be added inamounts large enough to inhibit bread loafing, but the desired structureof oil pockets is lost when glycerol is included in such amounts and thegrease must therefore be rejected. The problem involved is unusual andis peculiar to block greases, that is the greases which are relativelyhigh in soap content, anhydrous and are cooled by pouring into pans. Itmight be thought olfhand that a defoamant would inhibit bread loafingbut it is found that the outstanding oil defoamant, namely polymerizeddimethyl silicone, is ineffective for this purpose. onstrated thatdimethyl silicone polymer is not capable of suppressing the tendency tobreadloaf. Batches of double size, otherwise corresponding to Example I,were prepared with dimethyl silicone polymer to suppress foaming duringcooking in the kettle. This additive was successful for that purpose,thus permitting larger batches, but bread-dealing, batch uniformity andyield were the same with and without silicone polymer. The latter doesnot affect the characterizing ingredient of this invention, which actsthe same regardless of presence or absence of the silicone.

According to the present invention, bread loafing of block greases isinhibited while retaining the. desired structure. of the grease byadding to the batch a small amount, less than about 1 per cent byweight, of an oxygen containing surface active organic compound ofspecified nature. The

compounds effective for the present purpose are the monoand di-esters ofdibasic carboxylic acids with aliphatic alcohols. Typical compoundsWithin the scope of the invention are di-isobutyl adipate,di-Z-ethyl-hexyl sebacate, di-isobutyl sebacate, di-butyl phthalate,mono-2-ethyl hexyl adipate and similar compounds.

Example I This example represents manufacture of a typical commercialblock grease withoututilizing the principles .of thisinvention and issupplied for purposes of comparison to subsequent ex amples showing: thebenefits of the invention.

It has been dem- A thousand pound batch was prepared containing thefollowing ingredients:

' Weight percent Tallow 5.00

Hydrogenated fish oil 22.45 Caustic soda 5.40 Glycerine 0.55 Mineral oil66.60

A thousand gallon kettle is charged with all of the hydrogenated fishoil, tallow and mineral oil. This mixture is then heated to 250 F. byfire on the outside of the kettle. A portion about of the'alkali ismixed with an equal weight of water and heated to 200 F. and added tothe hot contents of the kettle. About minutes later the remainder of thecaustic soda is added to the kettle as a 50 per cent by weight solutionin water heated to about the same temperature as the kettle contents.After addition of the caustic soda, dehydration of the grease iscarriedon as rapidly as possible by heating to 500 F. and maintaining thattemperature until foam has subsided. The grease is then tapped from thebottom of the kettle into hand ladles from which it is poured into pansabout 4 x 6 x 46 inches. The pans are allowed to cool in the air, andthe grease is then trimmed and packed for shipping. In a typicalcommercial run the bread loafing in the first pans to be poured isextremely great, declining with successive pans and being practicablyunnoticeable in the last pans to be poured. Much of the grease is ofpoor structure and it is found that uniformity of the grease throughoutthe batch is highly unsatisfactory. Typically, upwards of 50 per cent ofthe batch must be rejected, with the rate of rejection being as high as60 per cent by weight for some batches.

Ezrample II Example III The batch of grease was similar to that ofExample II except that di-Z-ethyl-hexyl sebacate was used in an amountof 0.1 weight per cent. Slightly greater tendency to bread loaf wasfound in the first pans poured with no bread loafing in the last pans.Structure of the grease was satisfactory and marked improvements overthe blank run of Example I were found in yield and uniformity. The yieldwas 65 weight per cent,

Example IV The additive used in this batch was 0.05 weight per cent ofdi-isobutyl adipate. Marked improvement over the results of Example Iwere observed in bread loafing, structure and uniformity. The yield was'70 weight per cent.

Example V In this case 0.1 weight per cent of di-isobutyl' adipate wasincluded in the batch. Still further improvement over Example I wasobserved with, structure and uniformity at satisfactory. levels.

and only very slight bread loafing. The yield was weight per cent.

Example VI Di-butyl phthalate in an amount of 0.1 weight per cent wasused in the grease of Example I. Bread loafing was noticeably decreasedand satisfactory structure was obtained. While this additive is ofappreciable benefit, it is not as effective as the materials used inExamples II to V, inclusive, at this concentration. The yield was 60weight per cent.

Example VII Di-amyl sebacate is also effective but, like dibutylphthalate it does not give as satisfactory results as the other additivediscussed. At a concentration of 0.1 weight per cent, bread loafing wasappreciably reduced and satisfactory grease structure obtained. Theyield was 60 weight per cent.

Example VIII At a concentration of 0.1 weight per cent, di-Z-ethyl-hexyladipate also appreciably reduces bread loafing and gives satisfactorygrease structure. Here again the increased yield, namely 60 per cent, isnot as good as that obtained with the most effective of the additivesdiscussed.

Example IX Mono-2-ethyl-hexyl adipate gives intermediate improvement at0.1 Weight per cent concentration. There was some bread loafing in thefirst pans but none in the last and grease structure was satisfactory.Uniformity was improved and a yield of 60 weight per cent obtained.

Example X This example relates to a different type of block greaseprepared from the following constituents:

Weight per cent.

Mineral oil 67.75 Tallow 12.50 Hydrogenated fish oil 12.50 Caustic soda4.75 Calcium tallow soap 2.50

The kettle is charged with 80 per cent of the mineral oil together withall of the tallow and hydrogenated fish oil and a 50 per cent watersolution of the caustic soda. The mixture is heated to approximately 300F. and the calcium tallow soap added. Dehydration is then carried out asrapidly as possible to 350 F. at which time the remainder of the oil isadded. The grease isthen heated to 470 F. at which time it is drawn intopans of the type described above and allowed to cool before cutting andpacking. The tendency to bread loafing and poor structure is not asgreat as that of the grease described in Example I but it stillrepresents a serious economic consideration. The advantages of thisinvention are shown by comparison of yields when making the greasedescribed as compared with the same grease containing 0.1 Weight percent of di-Z-ethyl-hexyl sebacate. The yields are 65-70 weight per centfor the straight grease and 70-75 weight per cent for the greasecontaining di-Z-ethyl-hexyl sebacate.

We claim:

I. In a process for cooking a mineral lubricating oil fraction withmaterials selected from the group consisting of (1) fatty acid soaps and(2) fatty acids together with saponifying com-'v pounds to manufacturea. block-grease contain-1 ing, as the predominating constituentsthereof, mineral lubricating oil and a fatty acid soap, the improvementwhich comprises including in the cooking batch a small amount, less thanabout 1 per cent by weight, of an ester of a dibasic carboxylic acidwith an aliphatic alcohol.

2. In a process for cooking a mineral lubricating oil fraction withmaterials selected from the group consisting of (1) fatty acid soaps and(2) fatty acids together with saponifying compound to manufacture ablock grease containing, as the predominating constituents thereof,mineral lubricating oil and a fatty acid soap, the improvement whichcomp-rises including in the cooking batch a small amount, less thanabout 1 per cent by weight, of di-isobutyl adipate.

3. In a process for cooking a mineral lubricating oil fraction withmaterials selected from the group consisting of (1) fatty acid soaps and(2) fatty acids together with saponifying compounds to manufacture ablock grease containing, as the predominating constituents thereof,mineral lubricating oil and a fatty acid soap, the improvement whichcomprises including in the cooking batch a small amount, less than about1 per cent by weight, of di-Z-ethyl-hexyl sebacate.

4. In a process for cooking a mineral lubricating oil fraction withmaterials selected from the group consisting of (1) fatty acid soaps and(2) fatty acids together with saponifying compounds to manufacture ablock grease containing, as the predomintaing constituents thereof,mineral lubricating oil and a fatty acid soap, the improvement whichcomprises including in the cooking batch a small amount, less than about1 per cent by weight, of mono-Z-ethylhexyl adipate.

ALBERT B. OGDEN. RICHARD A. BUTCOSK. RAYMOND C. WILLIAMS.

REFERENCES CITED UNITED STATES PATENTS Name Date Morway Dec. 13, 1949Number

1. IN A PROCESS FOR COOKING A MINERAL LUBIRCATING OIL FRACTION WITHMATERIALS SELECTED FROM THE GROUP CONSISTING OF (1) FATTY ACID SOAPS AND(2) FATTY ACIDS TOGETHER WITH SAPONIFYING COMPOUNDS TO MANUFACTURE ABLOCK GRESE CONTAINING, AS THE PREDOMINATING CONSTITUENTS THEREOF,,MINERAL LUBRICATING OIL AND A FATTY ACID SOAP, THE IMPROVEMENT WHICHCOMPRISES INCLUDING IN THE COOKING BATCH A SMALL AMOUNT, LESS THAN ABOUT1 PER CENT BY WEIGHT, OF AN ESTER OF A DIBASIC CARBOXYLIC ACID WITH ANALIPHATIC ALCOHOL.